Abstract: The main objective of this experiment will be to evaluate the effectiveness of homologous scleral transplants to induce calcification for the purpose of apical closure of non-vital undeveloped teeth in dogs. Evaluation will include quantitative and qualitative analysis of the fibrous union of sclera to dental and periapical structures and subsequent calcification of the transplant. Specific Aims: 1. To determine whether fibroblasts migrate from periapical tissues into acellular sclera, forming a fibrous bond. 2. To determine the time period necessary to effect fibrous attachment. 3. To determine the nature and extent of scleral collagen calcification. 4. To determine the extent of structural change of periapical tissues. Methods: (Phase 1) Incompletely formed canines of 6 month old beagles will be devitalized. Periapical inflammation will be determined radiographically. Root canals will be debrided, prepared, treated and will then be recipients of scleral discs, scleral strips and Ca(OH) 2 plus CMCP mixture. Animals will be sacrificed at various time intervals yielding a dynamic interpretation of fibrous union and subsequent calcification of the transplanted sclera. Hematoxylin and eosin stain, koneff's and procion red dye markings will aid in evaluation of resulting sections. (Phase 2) Once these goals have been determined positively, selected undeveloped non-vital teeth in human patients will be treated using the scleral disc and strips. This method should effect a more favorable prognosis for non-vital open apex teeth.